Embolic protection during percutaneous heart valve replacement and similar procedures

ABSTRACT

Various devices are described to provide filtering of flow from the aorta to the left carotid artery and the right carotid artery. The filters can be brought into a desired position through one or more peripheral arteries. A single filter device can provide the desired filtering or a plurality of devices can be used. In particular a single filter device can span between the brachiocephalic artery and the left carotid artery. These filter devices can be used effectively to capture emboli generated during procedures on the heart so that emboli do not travel to the patient&#39;s brain where the emboli can cause a stroke or other adverse event. In particular, these filters can be used during percutaneous procedures on the heart, such as endovascular heart valve replacement.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of copending U.S. patentapplication Ser. No. 14/881,711 filed Oct. 13, 2015, entitled “EmbolicProtection During Percutaneous Heart Valve Replacement and SimilarProcedures,” which is a continuation of U.S. patent application Ser. No.13/398,577 filed Feb. 16, 2012, now U.S. Pat. No. 9,186,237 to Galdoniket al., entitled “Embolic Protection During Percutaneous Heart ValveReplacement and Similar Procedures,” which is a continuation of U.S.patent application Ser. No. 13/218,183 filed Aug. 25, 2011, now U.S.Pat. No. 8,382,788, entitled “Embolic Protection During PercutaneousHeart Valve Replacement and Similar Procedures”, which is a continuationof U.S. patent application Ser. No. 12/489,108 filed Jun. 22, 2009, nowU.S. Pat. No. 8,206,412 entitled “Embolic Protection During PercutaneousHeart Valve Replacement and Similar Procedures”, which claims priorityto U.S. provisional patent application Ser. No. 61/132,823 to Galdoniket al. filed on Jun. 23, 2008, entitled “Embolic Protection DuringPercutaneous Heart Valve Replacement and Similar Procedures”, all ofwhich are incorporated herein by reference.

FIELD OF THE INVENTION

The inventions, in general, are related to embolic protection devicesplaced in blood vessels during surgical intervention and correspondingmethods. The inventions are further related to embolic filters placed inblood vessels during percutaneous heart valve replacement, as well ascorresponding methods. The devices and methods can be directed to theprevention of the flow of emboli into the carotid arteries.

BACKGROUND

Less invasive procedures can provide desirable medical results withreduced recovery time and reduced risk to the patient. Thus, manysurgical procedures are performed using endoscopes or the like inpercutaneous formats. A large number of less invasive procedures withinthe cardiovascular system are now commonly performed, such asangiograms, angioplasty procedures and stent delivery procedures.

Heart valve prostheses have been successfully used to replace damagednatural heart valves that no longer perform their functions in asatisfactory way. Commercial heart valve prostheses include bothmechanical valves with rigid occluders and tissue-based prostheses withflexible leaflets. These valves have been implanted surgically throughthe chest with the patient on cardiopulmonary bypass.

SUMMARY OF THE INVENTION

In a first aspect, the invention pertains to a method for providingembolic protection comprising placing separate protective devices toinhibit emboli migration into the left common carotid artery and theright common carotid artery. The devices can be associated withindependent delivery devices or on a common delivery device. One or bothof the devices comprises a filter, and one of the devices can be anocclusive device. In some embodiments, the filter comprises fibers thatform a filtration matrix upon deployment. The device inhibitingmigration of emboli into the right common carotid artery can be withinthe right common carotid artery or within the brachiocephalic artery. Anaspiration catheter can be used to facilitate recovery of one or both ofthe devices. In some embodiments, one or both of the devices may beun-tethered. The devices can be deployed prior to performing apercutaneous valve replacement procedure, and the device can be removedfollowing completion of the procedure to replace a heart valve using apercutaneous procedure.

In a second aspect, the invention pertains to a method for providingembolic protection during endovascular procedures on a patient's heart.The method can comprise positioning one or more vascular filter elementsto filter flow into the right carotid artery, such as the right commoncarotid artery or the right interior carotid artery, and the leftcarotid artery, such as the left common carotid artery or the leftinterior carotid artery. Generally, each of the one or more vascularfilter elements are delivered through the right subclavian artery, theleft subclavian artery, or a combination thereof.

In a further aspect, the invention pertains to a filtration systemcomprising a catheter and a filter device. The catheter generallycomprises a tubular element having a proximal end and a distal end, alumen extending through the tubular element, and an expandable structuremounted toward the distal end on the exterior of the catheter. Thefilter device generally comprises a guide structure and a filter elementmounted on the guide structure, in which the lumen of the catheter issuitable for the delivery of filter element mounted of the guidestructure.

In another aspect, the invention pertains to a filtration systemcomprising a catheter, a first filter device and a second filter device.The catheter generally comprises a tubular element with a proximal endand a distal end, and a lumen extending through the tubular element. Thefirst filter device generally comprises a first guide structure and afirst filtration element attached to the first guide structure, and thesecond filter device generally comprises a second guide structure and asecond filtration element attached to the second guide structure. Thecatheter can have one or more lumens suitable for the delivery of thefirst filter device and the second filter device. Also, the catheter cancomprises a first port configured such that the first filter device canexit the catheter through the first port and a second port configuredsuch that the second filter device can exit through the second port atan angled direction relative to the first filter device exiting thefirst port.

In other aspects, the invention pertains to a filter device comprisingan overtube, a first corewire, a second corewire, a first filter elementhaving a delivery configuration and a deployed configuration, and asecond filter element having a delivery configuration and a deployedconfiguration, the first filter element being positioned distal to thesecond filter element. Generally, at least a portion of the firstcorewire and at least a portion of the second corewire are within theovertube. The configuration of the first filter element can becontrolled through the relative position of the first corewire and theovertube, and the configuration of the second filter element can becontrolled through the relative position of the second corewire and theovertube.

In additional aspects, the invention pertains to a filtration systemcomprising a first sealing member, a second sealing member, a lumenextending through the interior of each sealing member, and one or morefiltration elements associated with the lumen. The first sealing memberand the second sealing member can each have a configuration extendingoutward. The filtration elements can be configured such that flowthrough the lumen extending past the first sealing member and the secondsealing member passes through the one or more filtration elements.

Furthermore, the invention pertains to a method for the endovascularreplacement of a heart valve. The method comprises positioning one ormore filter elements to filter flow from the heart flowing into theright carotid artery and the left carotid artery, and delivering a heartvalve delivery catheter through the descending aorta or the subclavianartery to the heart to effect at least a step related to removal of aheart valve or the placement of a prosthetic heart valve.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of the aortic arch and major branchingarteries.

FIG. 2A is a sectional view of the aortic arch depicting two independentfilter elements placed respectively in the right carotid artery and leftcarotid artery through the right subclavian artery.

FIG. 2B is a sectional view of the aortic arch depicting two independentfilter elements placed into the right carotid artery through the rightsubclavian artery and into the left carotid artery through the leftsubclavian artery.

FIG. 3A is a sectional view of the aortic arch depicting a catheter withan external filter deployed to filter flow into the brachiocephalicartery and a filter device deployed through the catheter with a filterelement deployed in the left carotid artery.

FIG. 3B is a sectional view of the aortic arch depicting a catheter withan external occlusive element and an internal filter leading to a flowport proximal to the occlusive element, and filter device deployedthrough the catheter with a filter element deployed in the left carotidartery.

FIG. 3C is a sectional view of the catheter of FIG. 3B taken along lineC-C.

FIG. 3D is a fragmentary side view of the proximal end of the catheterof FIG. 3B with hidden structure shown in phantom lines.

FIG. 4 is a sectional view of the aortic arch depicting a catheter witha distal opening and a side opening along with a first filter devicedeployed through the distal opening of the catheter and a second filterdevice deployed through the side opening of the catheter.

FIG. 5 is a sectional view of the aortic arch depicting an un-tetheredfilter deployed in the right carotid artery and an un-tethered filterdeployed in the left carotid artery.

FIG. 6A is a side view of a filter device having a bundle of fibersforming a filter element on an integrated guide structure, in which thefilter element is shown in a low profile delivery configuration.

FIG. 6B is a side view of the filter device of FIG. 6A in which thefilter element is in a deployed extended configuration.

FIG. 7 is a fragmentary side view of the distal end of a rapid exchangecatheter having a filter that extends outward from the surface of thecatheter and with a bent tip that provides for improved tracking.

FIG. 8A is a side view of a filter device having a proximal filterelement and a distal filter element along a single integrated guidingdevice with a corewire that provides for the deployment and collapse ofthe filter elements, in which the filter elements are displayed in a lowprofile delivery configuration.

FIG. 8B is side view of the filter device of FIG. 8A in which the filterelements are shown in their extended deployed configuration.

FIG. 8C is a side view of alternative embodiments of a distal filterelement for incorporation in a filter device similar to the device inFIGS. 8A and 8B.

FIG. 8D is a sectional view of the filter element of FIG. 8C taken alongline D-D of FIG. 8C.

FIG. 8E is a fragmentary side view of the filter element of FIG. 8C inwhich a corewire has disengaged from a detachable element.

FIG. 9A is a side view of a filter device having a distal filter and aproximal filter along a single integrated guiding device with twocorewires that provide for the independent deployment and collapse ofthe distal filter element and the proximal filter element, in which thefilter elements are shown in a low profile delivery configuration.

FIG. 9B is a side view of the filter device of FIG. 9A in which thefilter elements are shown in an extended, deployed configuration.

FIG. 9C is a sectional view of the integrated guide structure of FIG. 9Ataken along line C-C.

FIG. 9D is a sectional view of the integrated guide structure of FIG. 9Ataken along line D-D.

FIG. 10 is a sectional view of the aortic arch depicting a filter systemwith a single filter element spanning between the left carotid arteryand the brachiocephalic artery.

FIG. 11A is a sectional view of the aortic arch depicting a filtrationdevice spanning between the left carotid artery and the brachiocephalicartery in which the filtration device comprises two occlusive elements,two internal filters and ports to provide filtered flow past theocclusive elements into the left carotid artery and the brachiocephalicartery.

FIG. 11B is a sectional view of the filtration device of FIG. 11A takenalong line B-B of FIG. 11A.

FIG. 12 is a sectional view of the aortic arch depicting a catheterextending into the ascending aorta from the descending aorta with anexternal filter element on the exterior of the catheter filtering flowwithin the ascending aorta.

FIG. 13A is a sectional view of the aortic arch depicting a filtrationdevice extending from the right subclavian artery into the left carotidartery in which the filter elements are in a low profile deliveryconfiguration.

FIG. 13B is a section view of the aortic arch depicting the filtrationdevice of FIG. 13A in which a distal filter element is in a deployedextended configuration.

FIG. 13C is a sectional view of the aortic arch depicting the filtrationdevice of FIG. 13A in which the distal filter element is deployed and aproximal filter element is exposed in a low profile configurationthrough the withdrawal of a sheath.

FIG. 13D is a sectional view of the aortic arch depicting the filtrationdevice of FIG. 13A in which the distal filter element is deployed andthe proximal filter element is deployed in an extended configuration.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Devices and corresponding procedures are described herein that cancapture emboli generated in procedures involving the heart, and inparticular the left chambers of the heart, to reduce or eliminaterelease of emboli into selected arteries, e.g., the carotid arteries. Itmay be desirable to perform procedures on the heart using less invasivetechniques that approach the heart through the blood vessels such thatopen heart surgery may not be needed. Any debris created in the vicinityof the heart that flows into the aorta can flow into the carotidarteries where the emboli can cause a stroke or other undesirableoutcome. In general, the filter system can be delivered independent ofthe heart treatment structures, such that the filters can be put intoplace at a desirable time, such as prior to events that can generateemboli. In some embodiments, portions of the filter system can bedelivered through one or both of the subclavian artery. In furtherembodiments, the filter system or portions thereof can be deliveredthrough the femoral artery. Various filter structures are described toperform the desired function of protecting, for example, the carotidarteries during percutaneous heart procedures, such as heart valvereplacement. These embolic protection devices can reduce risk associatedwith heart procedures to more desirable levels so that these procedurescan become more clinically acceptable alternatives to open heartprocedures. Furthermore, the filters can be also used in conjunctionwith procedures directly accessing the heart so that emboli which maycirculate after restarting the heart are captured by the filters so thatthey are not circulated to the patient's brain.

The devices described herein are designed to provide protection for thecarotid arteries, e.g., left common carotid artery and the right commoncarotid artery which are spaced apart with respect to their branchingrelative to the aorta. Thus, a single filter element can span asignificant length along the aorta or a plurality of filter elements canbe deployed. The right common carotid artery can be protected throughthe filtering of flow from the aorta into the brachiocephalic arterysince this artery leads from the aorta to the right carotid artery aswell as to the right subclavian artery at a branch. In some embodiments,a plurality of filters are placed on along a single guide structure suchthat a distal filter can be deployed to filter flow into the leftcarotid artery and a proximal filter can filter flow into thebrachiocephalic artery. In further embodiments, the filtration systemcomprises individual filters for filtering flow into the two carotidarteries while the delivery system can be configured to facilitate suchdelivery. With respect to the placement of individual filters, these canbe deployed further downstream the carotid arteries to protectspecifically the internal carotid arteries, which supply blood to thebrain, and the protection of the external carotid arteries is not assignificant since less critical tissues are supplied blood from theexternal carotid arteries. In additional embodiments, the filter systemcan be designed to have a single element span between the left commoncarotid artery and the brachiocephalic artery with controlled flow intothe respective arteries from the aorta such that the respective flowsare filtered. Thus, several filtration system designs are describedherein to provide a desired degree of filtration for flow from the aortato the carotid arteries.

Designs have been proposed for heart valve prostheses that can bedelivered and implanted in a percutaneous or endovascular procedure.Furthermore, percutaneous procedures can also be used to perform repairson heart valves that can reduce or eliminate the use of cardiopulmonarybypass. These procedures and other procedures on the heart generate arisk of emboli being released into the aorta. Emboli in the aorta canflow into the carotid arteries where they can be delivered into apatient's brain, which can result in a stroke and/or other adverseevents. In general, the flow of emboli into the descending aorta and/orthe subclavian arteries does generate a significant concern. Theembodiments of embolic protection devices described herein are designedto filter and/or block flow into the carotid arteries during the valvereplacement procedures and other heart procedures. Generally, theseprocedures are intended to be performed on human patients, although theprocedures and devices can also be used on farm animals, pets or otherdomesticated animals.

In general, it is desirable to maintain flow into the carotid arteriesduring the procedures so that blood flow to the brain is not disruptedfor significant periods of time. However, it is acceptable to block flowinto one of the carotid arties for a period of time if flow ismaintained into the other carotid artery. Therefore, the devices can bedesigned to filter flow into both carotid arteries or to block flow intoone carotid artery and filter flow into the second carotid artery.Blockage of flow can be performed with a balloon, an extendableocclusive device or the like. Balloon devices are well known in the art.In general, a balloon can be inflated through a lumen of the device withsaline or the like. Various filters are known in the art. For example,basket-type filters are commercially available.

Referring to FIG. 1, devices for endovascular procedures on the heartcan be brought up to the heart through the descending aorta generallythrough an incision in the leg. As shown in FIG. 1, aorta is shown witha heart valve delivery catheter 118. Arteries branching from aortic arch104 are also shown in the diagram. Filtration devices for providingembolic protection can be delivered in some embodiments through anartery in the patient's arm for tracking into right subclavian artery110 and, optionally into brachiocephalic artery 108. Once the filtrationdevice is delivered into the brachiocephalic artery, one or morefiltration elements can be positioned to filter flow into openings ofright common carotid artery 112 and left common carotid artery 114.Alternatively or additionally, a filtration device can also be deliveredthrough the patient's arm for tracking into left subclavian artery 116.Furthermore, filtration devices can be delivered from the descendingaorta to filter flow into one or both of the carotid arteries. Ingeneral, filtration devices can be delivered on a guide structure thatprovides for maneuvering the tip of the device to a desired locationwithin the vasculature. Alternatively or additionally, the devices canbe delivered on a catheter, which can be delivered over a suitable guidestructure.

With the objective of protecting the carotid arteries, such as thecommon carotid arteries, several filtration system types are describedherein. A first class of filtration systems has separate filter elementsto protect the individual carotid arteries. These systems may or may nothave specific catheter designs to facilitate the delivery of the filterelements. For example, the catheter can be designed to have a side portfor the delivery of a filter to the right common carotid artery from thebrachiocephalic artery following delivery of the catheter from the rightsubclavian artery. The filter elements can remain tethered to a guidestructure or the like, or the filters can be left un-tethered inposition for subsequent retrieval. In some embodiments, a filter elementfor the left common carotid artery can be delivered through the leftsubclavian artery to separate the delivery and retrieval of the twoseparate filters.

In additional embodiments, a plurality of filter elements can beattached to a single guide structure in which one filter element isdistal to another filter element. If the guide structure is deliveredalong the right subclavian artery, the distal filter element can beguided for deployment in the left common carotid artery. The device canthen be designed such that the proximal filter element is positioned fordeployment in the brachiocephalic artery such that it filters flow tothe right common carotid artery.

With respect to the filter elements, various ranges of filter designsare possible. In particular, membrane filter structures have beenincorporated into commercial embolic protection filters. Generally,these membrane based structures have large surface areas such thatreasonable flow can be maintained through the filter. To provide thedesired large surface area, these membrane based filters can have, forexample, a wind-sock shape, a conical shape or the like. Alternativefilter designs have been based on three dimensional filtration matrices.These filters can have an advantage with respect to a reduced lateralextent along the blood vessel in the patient while providing excellentfiltration with the maintenance of good flow through the filter.Suitable three dimensional filtration matrices can be formed frompolymer fibers, and surface capillary fibers have been found to beexcellent materials for the formation of filtration matrices, such aswith a mat of fibers.

In further embodiments, a filter device can comprise a single filtrationelement spanning between the opening of the brachiocephalic arterythrough to the left common carotid artery in which the device isextended to the walls of the vessel to control flow into the arteriesfrom the aorta. The extended portions can form a seal to the walls ofthe vessel using sealing elements. The structure can be deliveredthrough the right subclavian artery. Filtered flow is then allowed pastthe sealing elements through the respective interiors of the sealingelements. Suitable sealing elements can be, for example, a balloon, anextending scaffolding with a non-porous cover or the like. In someembodiments, the filtration element can comprise a filtration materialconnected to the sealing elements such that flow past the sealingelements flows through the filtration material. For example, thefiltration material can have a generally cylindrical shape spanningbetween the sealing elements to provide a large surface area forfiltration material. In alternative or additional embodiments, thefiltration element can have two filter elements with one filter elementassociated with each sealing element to filter the flow through thatparticular sealing element.

In additional or alternative embodiments, the sealing elements can beconnected with a tubular member having an opening to accept flow fromthe aorta. The tubular member can further comprise one or more filterelements within the tubular member between the opening to the aorticflow and the openings past the sealing elements into the respectivebrachiocephalic artery and the left common carotid artery. Thefiltration elements can be membrane based, fiber based, a combinationthereof or the like. These sealing member based structures can have theadvantage that the filter elements do not have to be transitionedbetween deployed and retrieval configurations in the context of deliveryand removal of the filter structure. The sealing members can be designedfor convenient deployment and collapse for removal. While the sealingmembers can reduce the diameter and thus the flow from the aorta, theuse of a device in which the filter elements are surrounded within atubular structure can reduce the risk of release of emboli during theremoval of the device without providing any additional steps to theprocedure.

In some embodiments, the heart procedures of particular involve anapproach to the heart from the descending aorta, around the aortic archand through the ascending aorta. In particular, endovascular heart valvereplacement can be performed as an alternative to heart valvereplacement involving open heart surgery. Other heart proceduresinclude, for example, heart valve repair, the repair of defects in theseptum separating heart chambers or other heart procedures that resultin a stroke risk. However, in additional or alternative embodiments, theheart can be approached through the chest to perform the procedure.Generally, the appropriate filters are deployed at an appropriate stagein the procedure prior to the creation of a significant risk of emboligeneration. Some procedures involve cardiopulmonary bypass to maintaincirculation during the procedure, and the filters can be deployed tocatch emboli that are generated as a result of the bypass procedureitself as well as the procedures on the heart.

As noted above, in some embodiments, a filter device may also be guidedthrough the descending aorta. For example, the filter can be mounted onthe exterior of a guide catheter that is positioned with its tip as wellas the filter element located within the ascending aorta between theaortic valve and opening into the brachiocephalic artery. The guidecatheter along with the mounted filter element can be positioned, forexample, before the heart procedure begins or at some other appropriateearly time in the procedure. The filter can be delivered to the locationin a lower profile configuration, and the filter can be deployed into adeployed configuration that directs the flow in the vessel around thecatheter through the filter element so that the down stream flow hasemboli removed by the filter.

With the filter in place, the heart procedure can then be performed withthe filter providing protection of flow into the body including thecommon carotid arteries. Tools for performing the heart procedure can beintroduced through the guide catheter without any interference by thefilter element. Following completion of the heart procedures or at leastthe steps of the heart procedure creating risk to the patient fromemboli generation, the guide catheter along with the filter can beremoved. The filter may be transitioned to a configuration to providefor removal, and various auxiliary devices, such as an aspirationcatheter or sheath can be used to facilitate the removal of the device,as described in more detail below in the context of specific devices.

In some embodiments, one or more filters are delivered through one orboth subclavian arteries. A filter element delivered from the rightsubclavian artery can be directly positioned for filtering flow into thebrachiocephalic artery, or the filter can be steered around a branchpoint for placement in the right common carotid artery. For placement inthe left common carotid artery, a filter element can be deliveredthrough the right subclavian artery, through the brachiocephalic artery,along the aortic arch a relatively short distance prior to entry intothe left common carotid artery. A filter can also be delivered into theleft common carotid artery from the left subclavian artery following arelatively short transit upstream along the aortic arch. In alternativeembodiments, the filters can be placed in an interior carotid artery asan alternative to a common carotid artery.

If a filter is placed within the right carotid artery, this filter wouldnot block access to the left carotid artery from the right subclavianartery by way of the brachiocephalic artery and the aortic arch.However, a filter placed in the brachiocephalic artery can block accessto the left carotid artery from the right subclavian artery unless thefilter is mounted on a catheter that provides an opening for the secondfilter to be delivered to the left carotid artery without allowingunfiltered blood to reach the right carotid artery. Thus, someembodiments of the filter system comprise a filter for thebrachiocephalic artery mounted on the outside of catheter that isdelivered into the patient prior to the delivery through this catheterof the filter for the left carotid artery.

A filter can also be placed within the brachiocephalic artery whileproviding access to the left carotid artery from the right subclavianartery if the two filters are mounted on a common guide structure. Theguide structure then provides for access to the left carotid arterywithout interfering with the filter for the brachiocephalic artery orcausing unfiltered flow that can go to the right carotid artery.Similarly, as noted above, a single filter structure can span betweenthe left carotid artery to the brachiocephalic artery along the aorticarch, which can involve seals at or near the openings to the respectivearteries.

For these embodiments with a single structure extending between the leftcarotid artery and the brachiocephalic artery, the guide structure witha mounted filter or filters, or a separate guide structure generally isdelivered into the left carotid artery after originating in the rightsubclavian artery. The filters and/or sealing elements can be deployedonce the tip is appropriately positioned in the left carotid artery. Therespective filters and/or sealing elements for the left common carotidartery and the brachiocephalic artery can be simultaneously deployed orsequentially deployed. The order of the deployment may depend on thestructure of the device in some embodiments. In particular, the devicemay be designed to intrinsically simultaneously deploy the elements.

In these embodiments, once the filtration structures are in place tofilter the flow into the left carotid artery and the brachiocephalicartery, then the procedures involving the heart can be performed withreduced or eliminated risk of emboli flowing into the carotid arteries.Once the heart procedures are completed, the filter structures can beremoved. In some embodiments, the respective filters and/or sealingmembers can be transitioned to a recovery configuration. In additionalor alternative embodiments, an aspiration catheter or sheath can be usedto facilitate the retrieval of the filter element(s), and the additionaltools may provide some protection against emboli being released from thefilter element during retrieval of the filter element.

The filter systems herein provide protection from the release of emboliinto the carotid arteries when performing procedures on the heart. Ingeneral, the heart procedures can involve access of the heart throughthe chest and/or through the descending aorta. Through the protection ofthe carotid arteries, the stroke risks can be significantly reduced. Thedevices and procedures are designed so that they should not interferewith the devices introduced for performing the heart procedure. Withappropriate filtration that does not significantly reduce the flow intothe carotid arteries, the filtration protection can be kept in place forheart procedures that take a significant period of time. Thus, thefiltration approaches provide a practical approach for the improvementof the outcomes resulting from procedures on the heart.

Filtration Devices

The filtration devices can incorporate various designs to accomplish theobjective of filtering flow from the aorta into the right carotid arteryand the left carotid artery. In general, the designs can be organizedinto 4 groups. In a first group, individual filter elements are used forthe respective right carotid artery and left carotid artery. In a secondgroup, a plurality of filter elements are mounted onto a common guidestructure with a structure that provides for delivery of a distal filterinto the left carotid artery while the proximal filter can be positionedfor filtration of flow into the brachiocephalic artery. In a thirdgroup, a single structure is designed to span from left carotid arteryto the brachiocephalic artery such that flow into both arteries isfiltered. In a forth group, a filter element is placed on the exteriorof a catheter for delivery into the ascending aorta such that flowaround the aortic arch, including flow into the carotid arteries, isfiltered. Devices for performing the heart procedure can be deliveredthrough the catheter with the filter element.

1. Individual Filter Elements for Common Carotid Artery Filtering

The filtration systems within this group have separate elements toprotect the respective left carotid artery and the right carotid artery.The filters can be placed in the common carotid arteries, oralternatively one or both filters can be placed past the common carotidartery and in the respective internal carotid artery. In general, thefilters or embolic protection devices can be tethered while the filtersare deployed to filter flow, or alternatively or additionally one orboth of the filters can be left in the vessel un-tethered at a positionto provide desired filtration of flow. An un-tethered filter can berecovered some time following the completion of a heart procedure.Suitable tethers include, for example, guide structures. Guidestructures, such as guidewires or integrated guiding devices, generallyprovide flexibility and maneuverability that provides for placement ofthe filters at desired positions. In some embodiments, a filter devicecomprises a single guide structure and a single filter element that aretracked into the brachiocephalic or a common carotid artery. If thefilter is deployed in an un-tethered configuration, a guide structure orthe like can be designed as a deployment tool, such as a sheath, forreleasing the filter at the selected location. An appropriate retrievaltool can be used to recover an un-tethered filter following completionof the procedures that motivated the placement of the filters.

Appropriate filter elements may be formed from a variety of materialsand can be designed such that sufficient blood flow is maintained evenunder moderate embolic loading. In some embodiments, filter elements maycomprise a three dimensional filtration matrix that provides for thecapture of emboli on the surface of the filter and/or within thefiltration matrix. The filtration matrix can provide for a large numberof alternative flow pathways through the matrix such that good flow canbe maintained through the filter even with a significant emboli loading.Additionally or alternatively, filter elements may comprise a baskettype filter element that comprises a filter membrane having distinctpores and generally a frame supporting the membrane. The basket openingcan be place across the vessel so that flow is directed into the basketwhere emboli are filtered. In further embodiments, filter elements cancombine three dimensional filtration matrices along with membrane basedfilter elements.

Referring to FIG. 2A, an embodiment is shown in which the protectiondevice comprises two separate filter elements that are delivered from aguide catheter. One of the filter elements is deployed in the leftcommon carotid artery, and the other filter element is deployed in theright common carotid artery. On or more retrieval catheters can be usedto facilitate the recovery of the filter devices. For example,fiber-based filter devices can be recovered effectively using anaspiration catheter as described in U.S. patent application2007/0060944A, now issued U.S. Pat. No. 8,021,351 to Boldenow et al.,entitled “Tracking Aspiration Catheter,” incorporated herein byreference. In alternative embodiments, the filter in one of the twocarotid arteries can be replaced with an occlusive device, such as aballoon.

FIGS. 2A and 2B illustrate filtration systems wherein independent filterelements are deployed, respectively, into the left common carotid arteryand right common carotid artery. Referring to FIG. 2A, filter system 128comprises a catheter 130, a first filter device 132 and a second filterdevice 134. Catheter 130 comprises a central lumen 136, through whichfirst filter device 132 and second filter device 134 can be delivered.In some embodiments, catheter 130 may comprise two lumens so that filterdevices 132, 134 can be separately tracked through catheter 130. Filterdevice 132 can comprise tether or guide structure 138 and filter element140. Similarly, filter device 134 can comprise tether or guide structure142 and filter element 144.

Filter elements 140, 144 can be attached to guide structures 138, 142,respectively, so that they may be independently or sequentially actuatedbetween their delivery and deployed configurations. In some embodiments,a filter element may comprise a self-expanding filter formed form shapememory polymers or metal alloys or other suitable material as describedbelow. In such embodiments, the guide structure may comprise a guidewireand the filter element may be welded, glued, or otherwise suitablyattached to the guidewire. In other embodiments, a guide structure maybe an integrated guiding device comprising a corewire and an overtube inwhich relative movement of the corewire and overtube can transition theattached filter element between its delivery configuration and deployedconfiguration. Suitable filter elements are described further below.

Referring to FIG. 2B, a filtration system 146 comprises two independentfiltration devices 148, 150 deployed through two separate catheters 152,154. Filtration device 148 comprises a tether or guide structure 156 anda filter element 158 attached to the tether 156 at or near its distalend. The distal end of tether 156 and filter element 158 may be trackedthrough a lumen 160 within catheter 152. Similarly, filter device 150comprises a tether or guide structure 162 and a filter element 164attach at or near the distal end of tether 162. The distal end of tether162 and filter element 164 may be tracked through a lumen 166 withincatheter 154. As depicted in FIG. 2B, catheter 152 is positioned withinright subclavian artery 110, and filter element 158 is positioned withinright common carotid artery 112 on tether 156. Furthermore, catheter 154is positioned within left subclavian artery 116, and filter element 164is positioned within left common carotid artery 114 on tether 162.Alternatively, filter 158 and/or filter 164 can be placed in thecorresponding internal carotid artery.

Referring to FIG. 3, in this embodiment a filter element is deployed inthe left common carotid artery. The guide catheter has an elementmounted along its exterior surface. This element can be a filter or anocclusive element, such as a balloon. FIG. 4 is an embodiment similar toFIG. 2, in which the guide catheter has a side port that provides forthe delivery of a device into the right common carotid artery throughthe side port. The device deployed into the right common carotid arterycan be an occlusive device such as a balloon.

Referring to FIGS. 3A and 3B, filter systems are shown in which adelivery catheter comprises a filter and/or an occlusive element whichcan replace one of the filter devices with respect to filter system 130of FIG. 2A. Referring to FIG. 3A, filter system 186 comprises a filterdevice 188 and catheter 190. Filter device 188 comprises a tether orguide structure 192 and filter element 194. Catheter 190 comprisestubular element 196 with a central lumen 198, and filter element 200that is attached at or near the distal end of tubular element 196.Filter element 200 can be designed with respect to configuration andsize for deployment in brachiocephalic artery 108. Filter device 188 canbe designed to extend from central lumen 198 for placement of filterelement 194 in left carotid artery 114.

Referring to FIG. 3B, filter system 202 comprises filter device 204 andcatheter 206. Filter device 204 comprises a tether or guide structure208 and a filter element 210. Catheter 206 comprises tubular element 212with a lumen 214 and an inflation lumen 215, occlusive element 216 andfilter element 218. Tubular element 212 has a distal port 220 and afiltered flow port 222. A cross section of tubular element 212 is shownin FIG. 3C. Occlusive element 216 can be, for example, a balloon orother extendable, non-porous structure. Inflation lumen 215 caninterface with occlusive element 216 at inflation port 224. Filterelement 218 is located within lumen 214 such that flow between distalport 220 and filter flow port 222 is filtered by filter element 218. Theproximal end of catheter 190 is shown in FIG. 3D. In this embodiment,the proximal end of tubular element 212 has a fitting 226, such as aLeur fitting. A side arm 228 connects an inflation source 230, such as asyringe, with inflation lumen 215, and inflation source 230 is connectedto arm 228 at fitting 232.

Filter element 218 may be formed from any suitable filter material orcombination thereof. Due to the location of filter element 218 withintubular element 212, filter element 218 can be fixedly attached in adesired configuration. For example, filter element can comprises a fiberfiltration matrix, such as surface capillary fibers, in a woven orunwoven mat, a porous filter membrane, or a combination thereof.Suitable porous membranes can be formed from comprising a sheetcomprising polymer and/or metal. Guide structure 208 can slide throughfilter element 218, for example, with a gasket or washer attached withinfilter element 218. A gasket or washer can be formed frompolytetrafluoroethylene or the like to produce a low friction interfacewith guide structure 208. Filter element 218 can be positioned withintubular element 212 while leaving a distal section into which filterelement 210 can be positioned during delivery into the vessel andwithdrawal from the vessel. Filter device 204 can be pre-loaded withrespect to catheter 206 prior to placement within the patient. Withfilter system 186, aortic blood flow into brachiocephalic artery 108through port 222 is filtered by filter element 218 and enters the rightsubclavian artery 173 and right common carotid artery 112.

FIG. 4 illustrates an alternative embodiment of a filtration systemsimilar to the system shown in FIG. 2A. Referring to FIG. 4, filtrationsystem 242 comprises catheter 244, first filter device 246 and secondfilter device 248. First filter device 246 and second filter device 248are analogous to first filter device 132 and second filter device 134 ofFIG. 2A. First filter device 246 comprises tether or guide structure 250and filter element 252 and is designed to extend from catheter 244 intothe right carotid artery 112. Filter device 248 comprises tether orguide structure 254 and filter element 256 and is designed to extendfrom catheter 244 into the left carotid artery 114.

Catheter 244 comprises a distal port 258 and a side port 260. Distalport 258 and side port 160 are designed for the delivery of a filterelement from lumen 262 within catheter 244 such that the filter elementand a tether extend out form the respective port to a deploymentposition. A deflection control catheter, such as catheter 244 canprovide support for a guide structure making a sharp turn since the sideport can help direct the tip of the guide structure in a desireddirection. Catheter 244 can be formed with an appropriate diameter toprovide for the delivery of two guide structures without interferencebetween the guide structures. Deflection catheters are described furtherin published U.S. patent application 2007/0208302 to Webster et al.,entitled “Deflection Control Catheters, Support Catheters, and Methodsof Use,” incorporated herein by reference.

Referring to FIG. 5, a filtration system 282 comprises detachablefilters 284, 286 that can be deployed in an un-tethered format withinthe arteries to provide desired filtration. As shown in FIG. 5, filterelements 284, 286 are deployed into the right carotid artery and leftcarotid artery, respectively. As described further below, filters 284,286 may be deployed using an appropriate delivery tool, and followingcompletion of a heart procedure that generates the risk of emboliproduction, a removal tool can be used to withdraw the filters so thatthey do not remain within the arteries.

While FIG. 5 shows un-tethered filters with one filter in the rightcommon carotid artery and one filter in the left common carotid artery.In alternative embodiments, an un-tethered filter can be placed in thebrachiocephalic artery, and/or one or both filters can be placed in acorresponding interior carotid artery. Furthermore, in some filtersystems, on filter can be tethered while a second filter is un-tethered.For example, an un-tethered filter can be placed in the left commoncarotid artery, and a tethered filter can be placed in the right commoncarotid artery. For embodiments with an un-tethered filter in the leftcommon carotid artery, the aorta can be free of structures relating tothe carotid filtering during portions of the procedure on the heart.

In the embodiments above in FIGS. 2-5, the filtration systems cancomprise various filter elements for appropriate deployment inassociation with a guide structure or for un-tethered deployment. Filterelements generally are designed to filter aortic blood flow into theleft carotid artery or right carotid artery such that sufficient flow ismaintained even under moderate embolic loading. In some embodiments, toperform the desired filtration, the filters can be designed to bedeployed into the brachiocephalic artery, right carotid artery, and/orleft carotid artery. For embodiments in which filter elements aredeployed in association with a guide structure or in an un-tetheredformat, the filter elements generally can be adapted from designs forother applications. In general, filter elements may comprise a threedimensional filtration matrix, a filter membrane, combinations thereofor the like.

A basket-type filter generally has a filtration membrane having poresdrilled, woven, molded or otherwise formed through the two-dimensionalmembrane. The size of the pores can be selected to allow passingbeneficial blood components while blocking emboli with sizes exceedingthe pore sizes. The shape of the basket can have the shape of a cone, awind sock or similar shape. Generally, the filtration membrane can besupported by a frame, struts or the like to provide a desired shape tothe filter structure. The expanded surface area of the basket can reduceclogging of the membrane for a particular loading of emboli. Suitablesizes of the pores can be determined for a particular application. Forgeneral applications in blood vessels, pores with a diameter from 50microns to 250 micron can be suitable. The porous membrane may comprise,for example, a polymer, such as polyurethane or polyester, metal orother suitable material that is attached to the frame member.

Generally, a frame member and/or struts of a basket filter can be made,for example, from a biocompatible metal, a suitable polymer or acombination thereof. Suitable biocompatible metals include, for example,titanium, cobalt, stainless steel, nickel, iron alloys, cobalt alloys,such as Elgiloy®, a cobalt-chromium-nickel alloy, MP35N®, anickel-cobalt-chromium-molybdenum alloy, and Nitinol, a nickel-titaniumalloy. In some embodiments, the frames can be designed to spontaneouslyassume an extended configuration when released in the vessel, while inother embodiments the frames can be actuated to assume a deployedconfiguration. Commercially available basket filters come in a varietyof frame sizes corresponding to the basket diameter. The frame size canbe chosen such that the edge of the basket contacts the vessel wallwithout damaging the vascular wall. Commercial basket filters include,for example RX Accunet®, an embolic protection device from AbbottLaboratories, Ill., USA, FilterWire™ from Boston Scientific Inc., MA,USA, and SpiderFX™ embolic protection device, from ev3, Inc., MN, USA,which comprises a basket filter with a windsock shaped Nitinol meshbasket that serves as the filter member. Self expanding basket filtersare described further, for example, in U.S. Pat. No. 6,740,061 to Oslundet al., entitled “Distal Protection Device,” incorporated herein byreference. Actuatable filter elements with a filtration membrane aredescribed further in U.S. Pat. No. 6,146,396 to Konya et al., entitled“Declotting Method and Apparatus,” and U.S. Pat. No. 6,663,652 to Danielet al., entitled “Distal Protection Device and Method,” both of whichare incorporated herein by reference. To aid with the selection of afilter size, reference vessel diameters may be obtained via angiography,quantitative angiography, ultrasound, or other suitable technique.

Matrix based filters generally can comprise a network of interconnectedand circuitous flow pathways through a three-dimensional mass ofmaterial. The availability of alternate flow pathways allow such matrixbased filters to maintain good flow even with moderate embolic loading.Generally a low pressure drop can be maintained across the filtrationdevice with a three dimensional filtration matrix after it is deployed.In some embodiments, a filter with a three dimensional filtration matrixcan have a significantly smaller lateral extent along a blood vesselrelative to basket type filter designs since the flow pathways throughthe filter matrix reduces the need for a large surface area to maintainflow under a moderate embolic loading.

In some embodiments, matrix material may comprise a swelling polymersuch as a hydrogel or shape memory fibers. Hydrogels are hydrophilicmaterials comprising polymers that are cross-linked to prevent them frombeing water soluble. When such materials contact aqueous solutions suchas blood or other bodily fluids, the material expands due to absorptionof fluid/liquid into the structure of the material. These types offiltration materials are described further in U.S. Pat. No. 7,303,575 toOgle, entitled “Embolism Protection Devices,” incorporated herein byreference.

In further embodiments, filters with three dimensional filtrationmatrices may comprise a bundle of fibers that are deployed into thefiltration matrix. Suitable fibers include, for example, surfacecapillary fiber (SCF) fibers. SCF fibers comprise fibers withchannels/grooves (surface capillaries) that run along the length of thefiber or a portion thereof. The presence of the channels increases thesurface area of the fiber relative to a non-channeled fiber with thesame radius (“round fiber”). For example, 4DG™ Fiber, an SCF fibercommercially available from Fiber Innovation Technology, Inc., JohnsonCity, Tenn., typically has 3 times the specific surface area of acomparable round fiber.

Referring to FIGS. 2-4, guide structures associated with tetheredfilters can comprise a guidewire, an integrated guiding device or thelike. As described herein, a guidewire has a long thin shape, which canhave a circular or non-circular cross section. In some embodiments, theguidewire can be, for example, a solid wire or a coil with a hollowinterior, optionally with a cover over the surface. Generally aguidewire is flexible for maneuvering within a patient's vasculature orother vessels within the patient, and the tip may be bendable tofacilitate steering of the guidewire.

As used herein, an integrated guide structure may be similar to aguidewire, but the integrated guide structure may comprise a structurewith components that move relative to each other. For example, anintegrated guide structure can have a corewire and an overtube such thatthe core wire and overtube can move longitudinally relative to eachother. In some embodiments, a torque coupler can couple the rotationalmotions of the corewire and overtube, which may also limit the range ofrelative longitudinal movement. Coils can also be added to the structureto increase the flexibility of the structure near the distal tip.

Referring to FIGS. 6A and 6B, a filter device 306 comprising an overtube308, a corewire 310 that extends within overtube 308, a handle 312 and afilter element 314. Referring to the side view in FIG. 6A, overtube 308has a tapered section 316 at its distal end. In this embodiment, aproximal coil 318 is abutted against and secured to tapered section 316.Corewire 310 is covered with a distal coil 320 at its distal end. Distalcoil 320 is connected with solder and a weld 322, although otherattachment approaches can be used. Overtube 308, corewire 310, proximalcoil 318, distal coil 320 and grip 312 can all be formed from stainlesssteel, although other suitable materials can be used as desired.Suitable actuation tools to provide for control of the relative movementof the corewire and overtube are described further in copending U.S.patent application Ser. No. 12/218,306 filed Jul. 14, 2008, now U.S.Pat. No. 8,070,694 to Galdonik et al., entitled “Fiber Based MedicalDevices and Aspiration Catheters,” incorporated herein by reference.

In this embodiment, filter device 314 comprises a bundle of SCF fibers324 attached at first attachment 326 and second attachment 328. A 0.1inch long tube 330, which can be formed from polyimide polymer, islocated within the second attachment 328 with corewire 310 extendingthrough the tube. The fibers are swaged/crimped/bonded at the twoattachments 326, 328, such as with radio-opaque bands. First attachment326 is attached to move with corewire 310, and second attachment 328 isattached to move with overtube 308 along with proximal coil 318. Aftercrimping, the fiber bundles can be bonded at each end with an adhesive,such as cyanoacrylate, and/or fused together with heat bonding.

The length of the fiber generally is chosen so that it is at least twiceas long as the radius of the vessel at the deployment site. The lengthcan be chosen so that in the deployed configuration, filter element 227effectively provides embolic protection while maintaining flow andwithout damage to the vascular wall. As mentioned above, referencevessel diameters may be estimated with angiography or other suitablemethod. Additionally, the fibers are generally aligned in a low profileconfiguration for delivery, and the fibers flare outward from thecorewire in a deployed configuration. The SCF fiber properties can bechosen so that when filter element 324 is in its deployed configuration,flow is adequately maintained in the vessel even with significantembolic loading. Further discussion on the selection of appropriatefiber characteristics as well as suitable materials for such anembodiment can be found in published U.S. Patent application number2006/0200047A, now issued U.S. Pat. No. 8,092,483 to Galdonik et al.,entitled “Steerable Device Having a Corewire Within a Tube andCombination with a Functional Medical Component,” incorporated herein byreference. Commercial filters with a structure similar to the device inFIGS. 6A and 6B with SCF fibers are available from Lumen Biomedical,Inc. under the name FiberNet®.

In some embodiments, a filter element can comprise a combination of athree dimensional filtration matrix with a basket type filter. Forexample, a fiber-based filter can be located within a basket such thatflow passes first through the filtration matrix and then through thefiltration membrane. The basket can form a stable frame to support thefiber-based filtration membrane, which can be desirable for high flowvessel. The basket can facilitate removal of the filtration matrix forcertain deployed placements.

The filter system described in FIG. 3A has a catheter with a filtermounted on the exterior of the catheter. Catheters, which can be adaptedfor current filtration applications, are described, for example, in moredetail in published U.S. patent application 2008/0172066 to Galdonik etal., entitled “Embolectomy Procedures With a Device Comprising a PolymerAnd Devices With Polymer Matrices and Supports,” incorporated herein byreference. A suitable embodiment of a catheter with an external filteris shown in FIG. 7, which also has a rapid exchange structure. Referringto FIG. 7, catheter 350 comprises a tubular element 352 with a bent tip354 and a distal opening 356. A rapid exchange port 358 provides forinsertion of guide structure 360 into tubular element 352, and guidestructure 360 can exit tubular element 352 at distal opening 356.

Overtube 362 rides over tubular element 352. Overtube 362 can have aslit or similar structure 364 to provide for the relative movement ofovertube 362 and tubular element 352 without interference from guidestructure 360. Since overtube 362 generally does not need to hold liquidsince tubular element 352 can define a central lumen, overtube 362 canhave a structure that is only tubular in the sense of being able to rideover tubular element 352 and transmit longitudinal movement from theproximal end of the device to the distal end of overtube 362. Fibers 366attach at a first end to tubular element 352 at first band 368, andfibers 366 attach at a second end to overtube 362 at second band 370.Relative movement of overtube 362 and tubular element 352 can be used totransition fibers 366 between a deployed, flared out configuration and astraighter configuration for delivery into and removal from a vessel. Asshown in FIG. 7, fibers 366 are in a flared out, deployed configuration,but a distal shift of tubular element 352 relative to overtube 362places the fibers in a straighter lower profile configuration. Fibers366 are generally arranged in a bundle, and fibers 366 can comprise SCFfibers to provide desirable filtration.

In some embodiments, un-tethered filter elements are placed in thevessels to provide desired filtration. These filtration systems arediscussed above in the context of FIG. 5. Commercial un-tethered filtersare available for deployment in veins, in particular the vena cava.These vena cava filters can be adapted for temporary placement forfiltering flow into the carotid arteries. Filtration membranes and/orfiltration matrices can be added to the vena cava filter designs toprovide greater control over emboli migration. Vena cava filters aredescribed further, for example, in U.S. Pat. No. 6,126,673 to Kim etal., entitled “Vena Cava Filter,” incorporated herein by reference.Un-tethered filters with three dimensional filtration matrices aredescribed further in U.S. Pat. No. 7,303,575 to Ogle, entitled “EmbolicProtection Devices,” incorporated herein by reference. In someembodiments, self-expanding un-tethered filters can be delivered from acatheter, in which the filters are pushed out from the catheter thatconstrains the filter in a delivery configuration. Upon release of aself-expanding filter, the filters deploy in the vessel. In alternativeembodiments, a specific deliver device can be used to deliver theun-tethered filter. Similarly, a retrieval device can be used to recoveran un-tethered filter. A retrieval device can grip or otherwise engagethe filter. Suitable retrieval devices for some un-tethered filterdesigns are described further in U.S. Pat. No. 6,726,621 to Suon et al.,entitled “Retrieval Devices for Vena Cava Filter,” incorporated hereinby reference. Similarly, grippers or micro-forceps that can be deliveredinto the vasculature through catheters can similarly be used to grip andremove un-tethered filter, which in some embodiments can be pulled intoa sheath or distal end of an aspiration catheter.

In general, any of the catheters described herein above or below cancomprise an over-the-wire design or a rapid exchange design. In a rapidexchange format, a guide structure exits a lumen through the side of thecatheter generally toward the distal end of the catheter such that theguide structure only engages the catheter over a portion of the lengthof the catheter. The catheters can be made from one or morebiocompatible materials, including, for example, metals, such asstainless steel or alloys, e.g., Nitinol, or polymers such aspolyether-amide block co-polymer (PEBAX®), nylon (polyamides),polyolefins, polytetrafluoroethylene, polyesters, polyurethanes,polycarbonates or other suitable biocompatible polymers. In someembodiments, the catheter can comprise a polymeric tubular structurereinforced with braided metal embedded in the polymer. Also, thecatheter tip may be curved or bent to improve tracking of the catheteron a guide structure. Rapid exchange catheters are described further inpublished U.S. patent application 2007/0060944A, now issued U.S. Pat.No. 8,021,351 to Boldenow et al., entitled “Tracking AspirationCatheter,” incorporated herein by reference.

2. A Plurality of Filter Elements on a Common Guide Structure

In some embodiments, a single guide structure can be constructed using aplurality of filter elements that are suitable to provide simultaneousfiltration of aortic blood flow into the left and right carotidarteries. Such filter devices can comprise a single guide structure withan attached proximal filter element and distal filter element. Theproximal filter element generally can be tracked into thebrachiocephalic artery and deployed, and the distal filter element canbe tracked through the brachiocephalic artery and into the left carotidartery for deployment. In this configuration, the flow through thedistal filter is in a proximal to distal direction relative to theorientation of the guide structure, and the flow through the proximalfilter is in a distal to proximal direction relative to the orientationof the guide structure. In some embodiments, the filters can be designedwith appropriate orientations based on the expected flow directions.

The filters generally have a low profile delivery configuration and anextended deployed configuration. In some embodiments, the guidestructure can comprise one or more corewires associated with anovertube, such that relative movement of the corewire(s) and theovertube can be used to transition the filters between their low profileconfiguration and the extended configuration. The filter device can beconstructed so that the proximal filter element and distal filterelement are either independently actuated or simultaneously actuatedbetween their low profile delivery configuration and deployedconfiguration. If the two filter elements can be independentlytransitioned between configurations, the proximal filter element and thedistal filter element can be sequentially transitioned betweenconfigurations to facilitate removal of the devices, as describedfurther below. In some embodiments, one or both filter elements can beself-extending following release from a sheath or the like.

FIGS. 8A and 8B show an embodiment with two filter elements that areattached to a common guide structure. In this embodiment, the twofilters generally are simultaneously deployed and subsequentlycollapsed. Filter device 390 comprises guide structure 392, proximalfilter element 394 and distal filter element 396. Guide structure 392comprises an overtube 398 and corewire 400. Overtube 398 and corewire400 can comprise elements of one or more torque couplers that providetorque coupling between overtube 398 and corewire 400. Generally,overtube 398 can move longitudinally relative to corewire 400, althougha torque coupler or other structure may limit the extent of the relativemotion. Suitable torque couplers can have a lock and key type ofinterface between structures along the surface of corewire 400 and theinner surface of overtube 398. Overtube 398 can comprise a contractingsection 402 near proximal filter 394 which allows for slight contractionof overtube 398 at that location decreasing the overall length ofovertube 398 to change the configuration of proximal filter 394.Contracting section 402 can be formed from weakened segments that aredesigned to fold upon the application of a moderate force, such as withan accordion type structure. Overtube 398 and corewire 400 may be formedfrom suitable materials for guide structures as described above.

In general, proximal filter 394 and distal filter 396 can have anyreasonable construction consistent with the attachment to the integratedguide structure. In particular filter element designs described abovefor individual placement of filter elements can be adapted for a tandemplacement of dual filters on a single guide structure. The placement oftwo filters based on three dimensional filtration matrices on a singleintegrated guide structure is described further in published U.S. patentapplication 2008/0172066A to Galdonik et al., entitled “EmbolectomyProcedures With a Device Comprising a Polymer and Devices with PolymerMatrices and Supports,” incorporated herein by reference. Filters withbaskets should be oriented so that the opening of the basket is orientedtoward the direction of the incoming flow. Thus, distal filter 396 canhave an opening facing the proximal direction relative to the guidestructure, and proximal filter 394 can have an opening facing the distaldirection relative to the guide structure. In some embodiments, one ormore of the filters can have both a basket shaped frame and a threedimensional filtration matrix.

As shown in FIGS. 8A and 8B, filter elements 394 and 396 comprise aframe with an associated filter matrix. Proximal filter element 394comprises frame 404 and fiber-based filtration matrix 406. Frame 404comprises struts 408, 410 and extendable cylindrical section 412. Struts408, 410 are configured to bend when contracting section 402 iscontracted, and the bent struts extend cylindrical section 412 into anextended configuration. Cylindrical section can comprise a pleatedstructure that unfolds to the extended structure upon deployment.Filtration matrix 406 can comprise a mat of fibers, such as SCF fibers.In some embodiments, one end of the fibers is attached to overtube 400and another end is attached to extendable cylindrical section 412 suchthat the filtration matrix 406 extends across the vessel whencylindrical section 412 is extended with an opening of the cylindricalsection oriented toward the distal end of filter device 394. Fibers canbe attached, for example, with adhesive, heat bonding, mechanicalclamping or combinations thereof.

Similarly, distal filter 396 comprises frame 414 and fiber basedfiltration matrix 416. Frame 414 comprises struts 418, 420 andextendable cylindrical section 422. Struts 418, 420 attach at one end toovertube 398 and at another end to cylindrical section 422. Cylindricalsection struts 424, 426 connect the lower edge of cylindrical section422 with corewire 400 at or near the distal end of corewire 400. Ifcorewire 400 is pulled in a distal direction relative to overtube 398,struts 418, 420 and cylindrical section struts 424, 426 flare outward attheir attachment to cylindrical section 422 as cylindrical section 422extends outward from overtube 398 to assume a deployed configuration, asshown in FIG. 8B. In the deployed configuration, fiber based filtermatrix 416 extends across the lumen of the vessel to filter flow passingthe filter. Filter matrix 416 can comprise a mat of fibers, such as SCFfibers, and fibers can be attached, for example, with adhesive, heatbonding, mechanical clamping or combinations thereof. Struts 408, 410,418, 420, 424, 426 may be formed, for example, from metal or metalalloy, such as stainless steel or Nitinol®, or other suitablebiocompatible material and may be welded, soldered, clamped,combinations thereof or otherwise suitably attached to appropriatestructures.

FIG. 8A shows filters 404, 406 in a low profile delivery configuration.If corewire is moved in a proximal direction relative to overtube 398,filters 394, 396 transition simultaneously to a deployed configurationas shown in FIG. 8B. In particular, contracting section 402 compresses,and struts 408, 410, 418, 420, 424, 426 bend as cylindrical sections412, 422 transition to an extended configuration. In the deployedconfiguration, cylindrical sections 412, 422 generally contact the wallsof the vessel such that flow past the filters passes through filtermatrices 406, 416, respectively. If corewire 400 is moved in a distaldirection relative to overtube 398, filters 394, 396 at least partiallycollapse to a lower profile configuration relative to the deployedconfiguration in FIG. 8B. The collapsed configuration of filters 394,396 may not return to the original configuration in FIG. 8A sincechanges in the materials upon deployment may not be fully reversible.

As shown in 8A and 8B, corewire 400 is fixedly attached to cylindricalsection struts 424, 426. In alternative embodiments, cylindrical sectionstruts can be attached to a detachable support that grips the corewire.In some embodiments, the structure providing the disengagement can beirreversible such that the corewire does not re-engage the filterelement when the corewire is moved in a distal direction relative to theovertube. Referring to FIG. 8C, a filter element 430 replaces filterelement 396 of FIG. 8B. Filter element 430 comprises mesh filter 431,cylindrical section 432, lower struts 433, 434, upper struts 435, 436and detachable support 437. Lower struts 433, 434 connect cylindricalsection 432 with overtube 438. Detachable support 437 connects upperstruts 435, 436 with corewire 439. Detachable support 437 comprisesfirst ring 440, first hinge 441, second ring 442 and second hinge 443.Rings 440, 442 can comprise rubber or other elastic material that gripscorewire 439 under moderate force, but releases corewire 439 undergreater force.

Based on the design of detachable support 437, if corewire 439 islaterally moved in a proximal direction relative to overtube 438,detachable support 437 grips corewire 439 to deploy the filter untilcylindrical section 432 contacts a vessel wall such that struts 435, 436cannot bend further. The extended configuration of filter element 430with an attached corewire 439 is shown in FIG. 8C. The sectional view ofFIG. 8D shows the extended upper struts 435, 436 with rings 440, 442engaging corewire 439. With the struts in a constrained configuration,further force on the corewire in a proximal direction relative to theovertube can disengage the corewire from rings 440, 442. Referring toFIG. 8E, when corewire 439 disengages from rings 440, 442, hinges 441,443 allow for the movement of rings 440, 442 relative to struts 435, 436so that corewire 439 does not re-engage rings 440, 442 if corewire 439is advanced in a distal direction.

Another filter device is illustrated in FIGS. 9A and 9B having twofilter elements attached to a common integrated guide structure. In thefilter device of FIGS. 9A and 9B, two separate corewires provide forindependent actuation of the two filter elements. Specifically,referring to FIGS. 9A and 9B, a filter device 446 comprises anintegrated guide structure 448, proximal filter element 450 and distalfilter element 452. Integrated guide structure 448 comprises an overtube454 and independent corewires 458 and 460. Overtube 454 comprises lumens462, 464, as illustrated in a section view of FIG. 9C, as well as ports466, 467 that are distal openings of lumens 462, 464, respectively. Atleast a portion of corewire 456 is within lumen 462 and extends fromport 466 of overtube 454. Similarly, at least a portion of corewire 458is within lumen 464 and extends from port 467 of overtube 454.Generally, corewires 456, 458 also extend from the proximal end ofovertube 454 such that the proximal ends of corewires 456, 458 can beused to manipulate independently the relative positions of corewires456, 458 and overtube 454. Corewires 456, 458 and overtube 454 canindependently comprise one or more torque couplers to restrain theangular motion of corewires 456, 458 within lumens 460, 462 and/or tolimit the longitudinal motion of the corewires relative to the overtube.

Filter element 450 comprises a basket filter 468 and a fiber basedmatrix filter 470 connected to the basket filter. Similarly, filterelement 452 comprises a basket filter 472 and a fiber based matrixfilter 474 connected to basket filter 468. Basket filter 468 comprises ahoop 476, a woven mesh 478 extending from hoop 476 and a strut 480.Strut 480 connects hoop 476 to overtube 454 in a distal directionrelative to woven mesh 478. Hoop 476 is connected to corewire 456 at aposition displaced from the location of the connection to strut 480 toapply appropriate torque to hoop 476 to transition the filter betweenconfigurations. FIG. 9A shows filter element 450 in a lower profileconfiguration. If corewire 456 is moved in a distal direction relativeto overtube 454, hoop 476 transitions to a deployed configuration, andstrut 480 flexes to support hoop in the deployed configuration. Wovenmesh 478 connects to hoop 476 at one end and to overtube 454 at theother end such that all flow through hoop 476 passes through woven mesh478.

Basket filter 472 comprises a hoop 482, a woven mesh 484 extending fromhoop 482 and a strut 486. Strut 486 connects hoop 482 to overtube 454 ina distal direction relative to woven mesh 484. Strut 486 extends alongwoven mesh 484. Hoop 482 is connected to corewire 458 at a positiondisplaced from the location of the connection to strut 486 to providefor suitable torque on hoop 482 to transition the filter betweenconfigurations. FIG. 9A shows filter element 452 in a lower profileconfiguration. If corewire 458 is moved in a distal direction relativeto overtube 454, hoop 482 transitions to a deployed configuration, andstrut 486 flexes to support hoop in the deployed configuration. Wovenmesh 484 connects to hoop 482 at one end and to overtube 454 at theother end such that all flow through hoop 482 passes through woven mesh484. The opening to woven mesh 484 through hoop 482 is oriented in aproximal to distal direction relative to overtube 454 while the openingto woven mesh 484 through hoop 482 is oriented in a distal to proximaldirection relative to overtube 454. These orientations of filterelements 450, 452 are consistent for placement respectively in thebrachiocephalic artery and left carotid artery with the guide structureextending form the right subclavian artery. Suitable materials for therespective elements are described above in the context of similarelements in different embodiments. Also, the respective elements can besimilarly attached as described above for the selected material.

As noted above, filter elements 450, 452 can be independently deployedand/or collapsed. As shown in FIG. 9A, filter elements 450, 452 areshown in a lower profile delivery configuration. As desired fordeployment, corewires 456, 458 can be moved independently in a distaldirection relative to overtube 454 to respectively deploy filterelements 450, 452. Similarly, corewires 456, 458 can be movedindependently in a proximal direction relative to overtube 454 tocollapse respectively filter elements 450, 452 for removal from thepatient.

3. A Single Filter Structure to Span Arteries Along the Aortic Arch

A single filter structure can be designed to span between arteriesbranching from the aorta along the aortic arch so as to providesimultaneous filtration of blood flow into the left carotid artery andthe right carotid artery. Such a filter structure may comprise a singlefilter element that spans the aortic arch between the brachiocephalicand left carotid arteries. Alternatively, such a structure may comprisemultiple filter elements attached to a single support structure thatspans the aortic arch when deployed. The filtration of flow into thebrachiocephalic artery correspondingly filters flow to the right carotidartery, which branches from the brachiocephalic artery.

FIG. 10 illustrates an embodiment of a filtration system 506 comprisinga catheter 508 and filter device 510 designed to span between thebrachiocephalic artery and the left common carotid artery. Filter device510 comprises a filter element 512 and tethers 514, 516. Tethers 514,516can extend through lumen 518 of catheter 508. Filter element 512comprises a proximal hoop 520, a distal hoop 522 and filter membrane524. Proximal hoop 520 generally is connected to tethers 514, 516. Ingeneral, one tether, three tethers or more than three tethers can beused as an alternative to two tethers. Hoops 522, 524 can comprise aresilient material such that the hoops can be placed in a lower profileconfiguration for delivery. The hoops material can be self-extendingsuch that the hoops extend to a deployed configuration when released inthe vessel, such as being removed from a sheath, catheter of the like.Tethers 514, 516 and filter element 512 may be formed from suitablematerials as described above. In its deployed configuration, filterelement 512 can be dimensioned so that its distal and proximal endsextend at least partially into left common carotid artery 114 andbrachiocephalic artery 108, respectively.

Referring to FIG. 11A, in a further embodiment, a filter device 542comprises tubular element 544, proximal occlusive element 546, distalocclusive element 548, proximal filter element 550, and distal filterelement 552. Tubular element 544 comprises a distal port 554, a centralport 556 and a proximal flow port 558. In this embodiment, occlusiveelements 546, 548 can be attached to the exterior of tubular element 544at suitable positions so that occlusive elements 546, 548 can bedeployed in brachiocephalic artery 108 and left common carotid artery114, respectively.

Occlusive elements 546, 548 can be balloons, although other occlusiveelements can be used, such as non-porous polymer membranes on aself-expanding metal frame that can be released from a sheath or thelike. If occlusive elements 546, 548 comprise balloons, tubular element544 generally comprises one or more inflation lumens. If a singleinflation lumen is used, occlusive elements 546, 548 are simultaneouslyinflated when an inflation fluid, such as sterile saline is directedinto the inflation lumen. An inflation lumen 570 is shown in phantomlines in FIG. 11A and in the sectional view in FIG. 11B. Inflation lumen570 is in fluid communication with occlusive elements 546, 548 throughinflation ports 572, 574, respectively. If a plurality of inflationlumen is used, occlusive elements 546, 548 can be independentlyinflated.

Proximal filter element 550 is positioned within tubular element 544between proximal flow port 558 and central port 556 such that flow intocentral port 556 is filtered prior to exiting proximal flow port 558.Similarly, distal filter element 552 is positioned within tubularelement 544 between central port 556 and distal port 554. Filterelements 550, 552 can be similar to filter element 218 of FIG. 3B. Aseparate guide lumen can be used to provide for placement of thecatheter in a desired location. Such a separate guide lumen can beplaced, for example, along the side of the catheter tubular element. Inthis way, a guide structure can be used for deployment withoutinterfering with the filter elements.

4. Catheter With an Exterior Filter to Filter Flow in the Aorta

In further embodiments, a filter can be delivered into the aorta tofilter blood flow from the ascending aorta into the aortic arch. Forexample, the filter can be delivered into the ascending aorta from thedescending aorta by way of a femoral artery, although other approachescan be used, such as from the left subclavian artery into the ascendingaorta. To maintain access to the heart through the aorta, the filter canbe mounted on the exterior of a catheter such that treatment instrumentsfor the heart can be introduced through the catheter. Through theplacement of a filter in the ascending aorta, blood is filtered not onlyfor the carotid arteries but also for the peripheral arteries.

Referring to FIG. 12, filtration catheter 580 comprises a tubularstructure 582 and a filter element 584. Tubular structure 582 has adistal port 586. Heart treatment tool 588 is shown extending from distalport 590 to access the heart through the ascending aorta. Catheters withexternally mounted filters are described above in the context of FIG. 3Aand FIG. 7. These catheters with external filter can be used in thecontext of the placement in FIG. 12 with appropriate sizing of thecatheter and filter.

Procedures for Embolic Protection During Heart Procedures

The filtration systems described herein can be effectively used forembolic protection during and/or following procedures on the heart. Inparticular, the filtration systems described herein can be used toprovide embolic protection during endovascular cardiac proceduresperformed in or around the left atrium and left ventricle of the heart,although the filter may also be useful for procedures on the heart withan approach through the patient's chest. Some procedures may involve anendovascular approach to the heart to accomplish certain steps of theprocedure and less invasive approaches through the patient's chest forother aspects of the procedure, such as providing cardiopulmonarybypass. The procedures on the heart can result in emboli that can flowfrom the aorta and then for circulation to other parts of the body.While emboli can be undesirable in any vessel, the circulation of emboliinto the carotid arteries, and in particular the internal carotidarteries, can result in the flow to the patient's brain where the embolican cause strokes or other adverse consequences. Therefore, it is verydesirable to filter emboli from the flow into the internal carotidarteries.

Thus, in some embodiments, filter elements may be positioned, forexample, in the ascending aorta such that emboli are reduced oreliminated from circulating to other parts of the body from the aorta.Additionally or alternatively, filter elements can be placed so thatemboli are removed from flow into the carotid arteries without removingemboli from flow through the descending aorta and/or one or both of thesubclavian arteries where emboli generally may not present a significantconcern. When the risk for emboli formation is reduced or eliminated,filter elements may be safely withdrawn from the patient in such a wayas to restrict emboli captured by the filter from entering the bloodflow into the carotid arteries.

Emboli can be released into the blood flow from various procedures onthe heart. In particular, heart valve replacement involves significantmanipulations of the heart tissue and can be associated with a risk ofemboli generation. Other heart procedures include, for example, heartvalve repair procedures. Emboli that are generated within or near theleft heart chambers may be released into the aorta upon resumption ofheart pumping if cardiopulmonary bypass is used. Emboli released intothe ascending aorta can flow downstream and may generate a risk ofemboli within the carotid arteries. In some embodiments, heartprocedures of interest include, for example, endovascular procedures inwhich instruments are delivered in a percutaneous format up an artery,such as the femoral artery or a subclavian artery to reach the heart.

While the filtering procedures described herein are applicable forprotection during various heart procedures, the procedures can beadvantageously used in conjunction with performing percutaneous heartvalve replacement. Generally, a percutaneous procedure to replace theaortic valve comprises delivery of a prosthetic heart valve through apatient's peripheral vasculature to an area at or near the valve root,such as the aortic annulus or the mitral valve annulus. The valvereplacement procedure may comprise the excising of the native valve,although in some embodiments, the replacement valve can be placed withinthe native valve without removing the native valve. The patient may beplaced on cardiopulmonary bypass to provide for oxygenated blood flowwhile the valve is being replaced. The prosthetic heart valve can bedelivered as a single unit or it can be delivered as a plurality ofsub-units and assembled in the patient's body. The procedure furthercomprises implantation of the prosthesis in the desired location. Wherethe prosthesis comprises a plurality of sub-units, the components of theprosthetic valve can be assembled prior to implantation and/or assembledwithin the patient.

An exemplary method for performing such a percutaneous valve replacementprocedure comprises the delivery of a compressible prosthetic aorticvalve comprising a tissue engaging base, designed to hold the prosthesisin place at or near the annulus of the native valve, and a leafletelement, designed to function as a valve. The prosthesis can comprise aplastically deformable structure that is designed to retain itsconfiguration when crimped for delivery. The prosthesis can be affixedto a delivery catheter comprising, concentrically, an outer sheath, anoptional push catheter, and a balloon catheter, and the prosthesis canbe attached to the balloon catheter such that when the balloon isinflated, the prosthesis adopts its expanded configuration. The cathetercan be tracked into the region of the valve annulus from a variety ofperipheral arteries or veins, for example, the left femoral artery orright femoral artery. The outer sheath can be tracked into the ascendingaorta from a peripheral artery, for example, using a variety of standardtechniques such as with the use of a guidewire. When the prosthesisreaches the desired location within the aortic annulus, the outer sheathis pulled back, exposing the prosthetic valve element. In appropriateembodiments, the balloon is then expanded, placing the prosthesis in itsexpanded configuration. The balloon is then deflated and the deliverystructure removed. For alternative embodiments in which the prosthesishas a self-expanding design, simply removing the prosthesis from theouter sheath can induce an expanded configuration. Further discussion onthis heart valve replacement procedure as well as alternativeembodiments can be found in U.S. Pat. No. 6,454,799 to Schreck, entitled“Minimally-Invasive Heart Valves and Methods of Use,” incorporatedherein by reference. Heart valve prostheses that can be placed in anaortic valve position or mitral valve positions with our withoutremoving the native valve are described further in U.S. Pat. No.7,329,278 to Seguin et al., entitled “Prosthetic Valve for TransluminalDelivery,” incorporated herein by reference.

The filtration systems described herein can be used to provide embolicprotection for selected vessels during a particular heart procedure. Thefilters are generally guided into position through a selected artery.The various filtration system designs described above are generallydesigned for delivery through a femoral artery or through one of thesubclavian arteries to access portions of the vessels that provide flowto the carotid arteries. The suitability of a particular artery for thedelivery of a filter can be evaluated with reference to considerations,such as the vessels to be provided with embolic protection, theparticular heart procedure being performed and the specific design ofthe filtration system being deployed. One or more guide catheters can bepositioned to facilitate the delivery and/or removal of the filters, andthe guide catheters may or may not remain in place during the time thatthe filters are within the patient's vessels. In general, the filtersand the associated structures should be designed appropriately to avoidinterfering with any tools used to perform the heart procedure. Forembodiments of the filtration system involving the placement of aplurality of filters, the vessel or vessels selected for theintroduction of the filters generally provide for the tracking of therespective filter elements to the desired locations sequentially orsimultaneously for appropriate timing for the placement of the filters.

In general, the filters can be deployed at a selected time, whichgenerally is prior to the time at which there is a significant risk foremboli generation. The appropriate timing for deployment of thefilter(s) generally depends significantly on the nature of the heartprocedure. In some embodiments, if the filters do not interfere with anyof the heart procedure steps or instruments, the filters can be deployedprior to any significant portions of the heart procedure. If good flowis maintained across the filters during the whole procedure, the filterscan be left in place for a significant period of time without anyadverse effects. In some embodiments, some steps of the heart proceduremay be performed prior to the placement of one or more filters. It maybe advantageous to deploy the filters at a later stage if the earlysteps of the heart procedure do not generate a significant embolic riskand/or if the early steps of the heart procedure could determine thatthe continuation of the heart procedure is contraindicated. The filtersthough are generally deployed prior to any significant risk of emboligeneration within the aorta.

After the significant risk for emboli generation has passed, thefiltration systems can be removed from the patient. In some embodiments,the filtration system can be removed after the heart procedure hascompleted. It may be desirable to continue filtration until aftercardiopulmonary bypass has been ended and the natural heart function hasbeen restored for a period of time. If some steps of heart procedure donot generate a significant risk from emboli or if the filter mayinterfere with some steps of the heart procedure, the filters may beremoved prior to completing all of the steps of the heart procedure. Ifsome portions of the filtration system are not needed at some stage ofthe procedure while other portions of the filtration system are desired,a portion of the filtration system maybe removed while another portionof the system can be kept in a deployed configuration. Furthermore, thefilters can be removed partially or completely at one stage in theprocedure and replaced with the same and/or different filters at a laterstage of the procedure.

Generally, to effectuate the removal of the filtration system from thepatient, the one or more filters can be collapsed to a recoveryconfiguration and removed from the vessel. The steps to accomplish theseobjectives depend significantly on the design of the filter(s). Forexample, some filters comprise an actuating component that can be usedto transition the filter to a lower profile recovery configuration. Insome embodiments, a filter may be collapsed with a sheath or the likethat is contacted with the proximal portion of the filter tomechanically collapse the filter, which may or may not also involve thewithdrawal of the filter partially or completely into the end of thesheath. In some embodiments, it may be desirable to drag the filter inan expanded configuration over a portion of the vessel prior to removalof the filter. For example, a filter in the left common carotid arterycan be dragged near the opening into the aorta where any emboli alongthe surface of the filter may be washed down the descending aorta wherethe emboli can generally be reasonably tolerated to reduce the risk ofemboli being released into the carotid artery during removal of thefilter.

In some embodiments, suction may be applied during some portion of theprocess to remove a filter from the vessel. If suction is applied, thetip of an aspiration catheter may be positioned near the filter andaspiration can be applied during the collapse of the filter to a lowerprofile configuration. The filter may be brought into the tip of theaspiration catheter, and the aspiration may be continued while thefilter is brought into the tip of the aspiration catheter. Theapplication of suction can be particularly desirable for filters withthree dimensional filtration matrices. The use of suction for therecovery of a filter device is discussed further in published U.S.patent application 2007/060944A to Boldenow et al., entitled “TrackingAspiration Catheter,” and published U.S. patent application 2005/0277976to Galdonik et al., entitled “Emboli Filter Export System,” both ofwhich are incorporated herein by reference.

In additional embodiments, it may be desirable to slide the device outfrom the carotid arteries. Upon exiting of the edge of the device, anyemboli along the surface of the device can be carried downstream fromthe opening of the carotid arties into vessels where the emboli will notcreate any significant concerns. This can be particularly useful forembodiments involving an occlusion device or for embodiments in whichthe design does not readily allow the placement of an aspirationcatheter adjacent the device.

The procedures described herein generally involve access to thepatient's vascular system through a small hole. Generally, the selectedvessel can be accessed, for example, with conventional tools, such asintroducers, cannula and the like. Hemostatic valves, leur fittings,other fittings and the like can be used to reduce bleeding from thepatient during the procedure. The fittings provide for the introductionand removal of various devices at appropriate times in the procedure.

1. Individual Filter Elements for Common Carotid Artery Filtering

As described above in the context of FIGS. 1-5, filtration systemswithin this group provide embolic protection to the left carotid arteryand right carotid artery using separate filtration devices. Thefiltration devices can comprise a guide structure and a single filterelement or filter elements to be deployed un-tethered. A method forproviding embolic protection with such protection systems comprisesdeployment and recovery of such systems. Deployment of such systemsgenerally comprises delivery of a filtration device to the right carotidartery or the brachiocephalic artery and deployment of the filterelement in an extended configuration. Deployment of the filtrationsystem generally further comprises delivery of a filtration device tothe left carotid artery and deployment of the filter element in anextended configuration. Recovery of such systems generally comprisesplacing deployed filter elements in a recovery configuration andwithdrawing the filtration system from a patient's body generallywithout significant release of emboli are not released into the carotidarteries.

Referring to FIG. 2A, guide catheter 130 can optionally be used tofacilitate the subsequent delivery of filtration devices. The guidecatheter can be positioned, for example, using conventional techniques.Specifically, as implied in FIG. 2A, deployment of the filtrationdevices comprises introduction of guide catheter 130 into a patient andtracking the distal end of the guide catheter into the right subclavianartery. Filter devices 132, 134 can then be delivered through the guidecatheter sequentially or simultaneously. The distal ends of filterdevices 132, 134 are tracked respectively to the right carotid arteryand the left carotid artery. Once the filter elements are at theirdesired positions, the filter elements can be deployed. The deploymentof the filters depends on the design of the filters. For example,self-extending filters can be deployed through the withdrawal of acovering sheath such that the filters can extend to their deployedconfiguration. In other embodiments, the filter elements can be actuatedto their deployed, extended configuration. For example, the filter ofFIGS. 6A and 6B can be actuated by pulling the corewire in a proximaldirection relative to the overtube. As shown in FIG. 2A, filter element140 is delivered within the right common carotid artery, and filterelement 144 is delivered into the left common carotid artery, althougheither filter can be alternatively delivered into the correspondinginternal carotid artery.

Recovery of the filtration system illustrated in FIG. 2A comprisesplacing filter elements 140, 144 into a recovery configuration andwithdrawing filter devices 132 and 134 from the patient's body throughcatheter 130. In some embodiments, filter device 132 and/or filterdevice 134 can be de-actuated to place the filter in a recoveryconfiguration. For example, the filter device of FIGS. 6A and 6B can bede-actuated by pushing the corewire in a distal direction relative tothe overtube. Where aspiration is desirable for either filter element140,144, catheter 130 can be removed from a patient's body and anaspiration catheter can be delivered to either filter element 140, 144over guide structures 138, 142, respectively. Alternatively, if guidecatheter 130 has a large enough diameter, aspiration catheters can betracked through the guide catheter. For self-extending filter elements,a catheter can be brought up to the filters to mechanically collapse thefilters, and these retrieval catheters can be brought up to the filterssimilarly as the aspiration catheters.

With the filtration system illustrated in FIG. 2B, similar methods canbe used as the methods described above for the filtration system in FIG.2A. Referring to FIG. 2b , deployment of the filtration system comprisesdelivery of guide catheters 152, 154 into the right subclavian arteryand left subclavian artery, respectively. Subsequently, filter devices148, 150 are tracked into the right common carotid artery and the leftcommon carotid artery, respectively. The deployment of the filters andrecovery of the filters can be performed as previously described for thesystem in FIG. 2A. The filtration system in FIG. 2B avoids any possibleinterference associated with the use of a common guide structure, butthe methods for the deployment of the filtration system in FIG. 2Binvolve two entry points into the patient for filter delivery incontrast with the single entry point used for the filtration system ofFIG. 2A.

With respect to the procedures relating to the filtration systems inFIGS. 3A and 3B, catheters 190 or 206 replace first filter device 132.Filter devices 188 (FIG. 3A), 204 (FIG. 3B) can be delivered into theleft carotid artery similar to the delivery of filter device 132 (FIG.2A), and the deployment and retrieval of filter devices 188, 204 canalso be similar to the corresponding steps for filter device 132.Referring to FIG. 3A, catheter 190 generally can be put in place priorto or after the placement of filter device 188. Similarly, filterelement generally 200 can be deployed prior to or after the deploymentof filter element 194. If filter element 194 is a self-expanding filter,catheter 190 can be put in place after the deployment of filter element194 if catheter 190 has the potential of interfering with the deploymentof filter 194. With respect to the order of retrieval of the filters,catheter 190 and filter device 188 can be retrieved in either order ifno additional structured are used in the process. If a suction catheteror other catheter is used in the retrieval of filter element 194, filterelement 200 can be collapsed first to allow for the removal of catheter190 or for the use of catheter 190 to facilitate the retrieval of filter194 by advancing catheter 190 to filter 194. Filtration system 202 inFIG. 3B can be manipulated similarly to filter system 186 in FIG. 3Awith the appropriate deployment and collapse of occlusive element 216substituted the deployment and collapse of filter element 200.

With respect to filtration system 242 shown in FIG. 4, catheter 244 andfilter device 248 generally can be delivered in either order. However,catheter 244 is delivered with its distal end in the brachiocephalicartery prior to the delivery of filter device 246 since the delivery offilter device 246 is effectuated through a port of catheter 244.Similarly, catheter 244 can remain in a deployed position while filterdevice 246 is retrieved. Catheter 244 and filter device 248 generallycan be removed from the patient in either order or simultaneously.

Referring to FIG. 5, filters 284, 286 generally are deployed with asuitable delivery tool and removed with a corresponding removal tool.The delivery tool may or may not be the same as the removal tool.Suitable delivery tools and removal tools are described above. Ingeneral, the filters can be delivered and retrieved independently, andthe delivery and removal of filters 284 and 286 generally can beselected to be in any order. The delivery and removal tools generallycan be tracked to the desired locations through any peripheral artery,such as a subclavian artery or a femoral artery.

2. A Plurality of Filter Elements on a Common Guide Structure

In some embodiments, a filtration system is deployed system forfiltering flow to the carotid arteries that has a plurality of filterelements on a common guide structure. The method involving the use ofthese filter devices generally comprises deployment and recovery of theprotection system in which the device scans a section of the aortic archbetween the left carotid artery and the brachiocephalic artery. Thefilter devices comprise a guide structure, a proximal filter elementattached to the guide structure, and a distal filter element attached tothe guide structure. The guide structure can be an integrated guidingdevice with one or more corewires within an overtube to facilitatedelivery and/or collapse of the device. Generally, the filter device istracked through the right subclavian artery into the brachiocephalicartery and to the left common carotid artery so that the proximal filterelement filters flow to the right carotid artery and the distal filterelement filters flow to the left carotid artery. Subsequently, thefilter elements can be simultaneously or sequentially placed into adeployed configuration. Recovery of a filtration system with two filterson a guide structure generally comprises sequentially or simultaneouslyplacing the filter elements in a recovery configuration, which candepend on the design of the filters. The protection device issubsequently removed from a patient. In some embodiments of the method,placing any or all of the filter elements in a recovery configurationand/or removing a protection device can be done under aspiration.

FIGS. 13A-D illustrates a method for providing embolic protection usinga filter system comprising a plurality of filter elements on a commonguide structure. The methods for using these filter devices can beapplicable for the filter devices in FIGS. 8 and 9. Thus, in someembodiments, the guide structure can comprise an inner core(s) thatactuate filter element(s) either sequentially or simultaneously betweena delivery and deployed configuration. In other embodiments, the filterelements can comprise self-expanding structures that adopt a deployedconfiguration when a constraint is removed. Referring to FIG. 13D,elements of a filter device 608 comprises a proximal filter element 610,a distal filter element 613, and a guide structure 614.

Referring to FIG. 13A, the method of using filter device 608 comprisesdelivery of a delivery catheter 616 through the right subclavian arteryand into the left common carotid artery such that distal filter elementis within the left carotid artery. Subsequently, protection device 608is tracked through delivery catheter 616 so that filter element 612extends completely from delivery catheter 616 and is positioned in adesirable location. Where filter element 612 comprises a structure thatdoes not spontaneously assume a deployed configuration when extendedcompletely through delivery catheter 616, filter element 612 is thenactuated into a deployed configuration, as shown in FIG. 13B. Referringto FIG. 13C, delivery catheter 616 is then moved proximally with respectto filter element 612 until filter element 610 extends complete fromdelivery catheter 616. Where filter element 610 comprises a structurethat does not spontaneously assume a deployed configuration whenextended completely from delivery catheter 616, filter element 612 isthen actuated into a deployed configuration, as shown in FIG. 13D. Then,catheter 616 and be left in place, withdrawn further, or completelywithdrawn from the patient's body.

An appropriate embodiment of a recovery method varies with the type offilter element deployed. Generally, a recovery method comprises placingproximal filter element 610 and distal filter element 612 intorespective recovery configurations. If filter element 610 isself-expanding, an external constraint can be introduced to mechanicallytransition filter element 610 into a recovery configuration. Forexample, delivery catheter 616 or an introduced aspiration catheter canbe used as such a constraint. Furthermore, if filter element 612comprises a self-expanding structure, an external constraint, such asdelivery catheter 616 or a separate catheter, can be introduced tomechanically transition distal filter element 612 into a recoveryconfiguration. In further embodiments, an actuation element, such as acorewire, can be used to transition the filter elements into a lowerprofile recovery configuration. In general, the proximal filter element610 and distal filter element 612 can be sequentially or simultaneouslytransitioned into a recovery configuration. Filter device 608 can bewithdrawn through catheter 616 or separate from catheter 616. With theembodiment of the filter device in FIGS. 8C-E, the proximal and distalfilters are deployed using the corewire to actuate the deployment. Tocollapse the filters, the proximal filter is collapsed using thecorewire while the distal filter is collapsed mechanically, for example,using a catheter or sheath to push against the lower struts. In thisway, the two filters can be sequentially collapsed using a device with asingle corewire.

For embodiments in which filter device 608 comprises filter elementsthat can be sequentially or independently actuated between a deployedconfiguration and a recovery configuration, proximal filter element 610and/or distal filter element 612 can be placed into a recoveryconfiguration under aspiration. In particular, an aspiration cathetercan be introduced over guide structure 614 to a location proximal toproximal filter element 610 and, subsequently, proximal filter element610 can be placed into a recovery configuration. The aspiration cathetercan then be placed at a location proximal to distal filter element 612.Subsequently, distal filter element 612 can be place into a recoveryconfiguration and protection device 608 can be removed with or withoutaspiration.

3. A Single Filter Structure to Span Arteries Along the Aortic Arch

A method for providing embolic protection during a heart procedure cancomprise deployment and recovery of a protection system comprising asingle filter structure that spans along the aortic arch. Morespecifically, a method for providing embolic protection with theseembodiments of a filtration system comprises deploying a portion of thefilter structure within the brachiocephalic artery and a portion of thefilter structure within the left carotid artery. Generally, the filterstructure is tracked through the right subclavian artery through to theleft carotid artery. The filter structure is deployed with the filter inthe desired location. The filter can comprise elements that areself-expanding or elements that are actuated for deployment. In anycase, the deployed filter element generally has elements that at leastapproximately seal with the carotid artery and the brachiocephalicartery such that flow from the aorta is filtered into these arteries.Furthermore, the method of using these filter devices further comprisesrecovery of the filter structure. Generally, recovery of a filterstructure comprises placing the filter structure in a recoveryconfiguration and removing the filter structure from a patient's body.Placing a filter structure and/or removing the filter structure from apatient can be done with or without aspiration.

With the filtration system illustrated in FIG. 10, a method for embolicprotection comprises deployment and recovery filter structure 510. Amethod for deploying filter structure 510 can comprise delivery ofcatheter 508 through the right subclavian artery and into the leftcarotid artery. The deployment method further comprises delivery of thefilter structure 520 through a central lumen 518 through catheter 508.Filter structure 520 can be preloaded within catheter 508, or filterstructure 520 can be tracked through catheter 508 following placement ofcatheter 508 within the vessel. In some embodiments, filter structure520 can be placed within catheter 508 for delivery so that distal hoop522 and proximal hoop 520 is located within catheter 522 in a lowerprofile configuration. Subsequently, the deployment comprises movingcatheter 508 proximally relative to filter structure 510 so that distalhoop 522 extends completely from catheter 508 and within the left commoncarotid artery. Catheter 508 is further moved proximally to filterstructure 510 so that a filter element 512 extends completely fromcatheter 508 and so that proximal hoop 520 is located within thebrachiocephalic artery. Proximal hoop 520 and distal hoop 522 can beself-deploying such that these hoops assume an extended configurationforming a seal with the vessel walls upon release in the vessel.Subsequently, catheter 508 can be partially withdrawn, completelywithdrawn, or left in place.

Recovery of filter structure 510 can comprise moving catheter 508distally along tethers 514, 516 and over filter structure 510 so thatfilter structure 510 is completely contained within catheter 508.Proximal hoop 520 and distal hoop 522 can be formed of a resilientmaterial such that mechanical forces distort the hoops for recovery intocatheter 508. In some embodiments, tethers 514, 516 can be used to pullfilter element 510 in a deployed configuration to displace emboli on thesurface of such that the emboli flow down the descending aorta intovessel in which the emboli would not generally cause any significantadverse effects. If these emboli flow down the descending aorta, theemboli are not present to flow into the carotid arteries, where theemboli can cause significant adverse events. After filter structure 510is withdrawn into catheter 508, filter structure 510 can be removedthrough catheter 508 or filter can be removed simultaneously withcatheter 508. In other embodiments of the recovery method, an aspirationcatheter can be substituted for catheter 508.

With respect to the filter system in FIG. 11A, catheter/tubular element544 is tracked through the right subclavian artery such that the distaltip is within the left carotid artery. When tubular element is inposition, occlusive elements 546, 458 are deployed to form seals againstthe vessel walls. With the design shown in FIG. 11A, occlusive elements546, 548 are simultaneously deployed, although in alternativeembodiments, it may be possible to sequentially deploy occlusiveelements 546, 548, such as if there are separate inflation lumens. Onceocclusive elements 546, 548 are deployed flow from the aorta into thecarotid arteries is filters. To remove the filter system from thepatient, occlusive elements 546, 548 are deflated or otherwisetransitioned to a recovery configuration unsealed from the vessel walls.Then, the filter device can be removed from the vessel. The placement ofthe filter elements within tubular element 544 protects the filters toreduce the change that emboli become displaced during removal of thefilter device.

4. Catheter With an Exterior Filter to Filter Flow in the Aorta

With respect to the deployment of filters within the ascending aorta onthe exterior of a catheter, the catheter can be tracked into positionprior to the commencement of the procedure on the heart. Generally, thecatheter is delivered into the ascending aorta with the filter element,such as filter 584 of FIG. 12, in a low profile delivery configuration.Once in position, the filter element can be deployed into an extendedconfiguration. Desired devices for the heart procedure can be trackedthrough the catheter. After completion of the procedures that create arisk of emboli generation, the filter element can be transitioned to arecovery configuration, and the catheter with the collapsed filterelement can be removed. The recovery of the catheter and filter elementcan be assisted with an aspiration catheter.

Distribution And Packaging

The medical devices described herein are generally packaged in sterilecontainers for distribution to medical professionals for use. Thearticles can be sterilized using various approaches, such as electronbeam irradiation, gamma irradiation, ultraviolet irradiation, chemicalsterilization, and/or the use of sterile manufacturing and packagingprocedures. The articles can be labeled, for example with an appropriatedate through which the article is expected to remain in fully functionalcondition. The components can be packaged individually or together.

Various devices described herein can be packaged together in a kit forconvenience. The kit can further include, for example, labeling withinstruction for use and/or warnings, such as information specified forinclusion by the Food and Drug administration. Such labeling can be onthe outside of the package and/or on separate paper within the package.

The embodiments above are intended to be illustrative and not limiting.Additional embodiments are within the claims. In addition, although thepresent invention has been described with reference to particularembodiments, those skilled in the art will recognize that changes can bemade in form and detail without departing from the spirit and scope ofthe invention. Any incorporation by reference of documents above islimited such that no subject matter is incorporated that is contrary tothe explicit disclosure herein.

We claim:
 1. A method for providing embolic protection during an endovascular procedure on a patient's heart using a filtration system, comprising a tubular element, a first sealing member and a second sealing member spaced apart and attached to a distal section of the tubular element, with the first sealing member distal to the second sealing member, a central port in the tubular element between the first sealing member and the second sealing member providing opening into a lumen extending past respectively the first sealing member and the second sealing member, and one or more filtration elements associated with the lumen at the distal section of the tubular element wherein the first sealing member and the second sealing member each having an extending outward deployed configuration and a delivery configuration, and wherein the one or more filtration elements are configured such that fluid flows through the central port into the lumen, by passes respectively the first sealing member and the second sealing member and exits the tubular element through the one or more filtration elements, the method comprising, delivering the filtrations system to position the central port in an aortic arch, the first sealing element in a left carotid artery, and the second sealing element in a brachiocephalic artery; deploying the sealing members to occlude the blood flow directly into the carotid arteries from the aorta while allowing blood flow to enter the lumen through the central port and exit the tubular element through the one or more filtration elements as filtered blood flow into the carotid arteries, by passing the first sealing member and the second sealing member.
 2. The method of claim 1 further comprising performing an endovascular procedure on the heart while the filtration system is filtering flow into the carotid arteries.
 3. The method of claim 2 wherein the procedure comprises replacement of an aortic valve.
 4. The method of claim 1 further comprising performing a surgical procedure on the heart while the filtration system is filtering flow into the carotid arteries.
 5. The method of claim 1 further comprising delivering a heart valve delivery catheter through a descending aorta or a subclavian artery to the heart to effect at least a step related to removal of a heart valve or the placement of a prosthetic heart valve.
 6. The method of claim 1 further comprising removing the filtration system from the arteries following performance of an endovascular procedure on the heart.
 7. The method of claim 6 wherein at least a part of the removal process is accompanied by aspiration. 